Electric power steering system, control method and device therefor, and vehicle

Abstract

A control method for an electric power steering system, comprising: when a vehicle ignition signal is abnormal, acquiring a steering wheel torque signal and a vehicle speed signal (S1); when the vehicle speed signal is abnormal and the change rate of the steering wheel torque signal is greater than a preset threshold, on the basis of a first preset vehicle speed, controlling the electric power steering system to provide steering assistance (S2); and when the vehicle speed signal is abnormal and the change rate of the steering wheel torque signal is less than or equal to the preset threshold, controlling the electric power steering system to stop providing the steering assistance (S3). Further disclosed are an electric power steering system using the control method, and a vehicle. According to the control method for the electric power steering system, when a vehicle ignition signal is abnormal, on the basis of a steering wheel torque signal and a vehicle speed signal, the electric power steering system is controlled to perform steering assistance on a vehicle, thereby avoiding potential safety hazards caused by a steering assistance anomaly, and improving the safety of the vehicle.

Description

Electronic power steering system, control method, device and vehicle thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410256305.2, filed on March 6, 2024, entitled “Electronic Power Steering System, Control Method, Device and Vehicle Thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of vehicle technology, and in particular to a control method for an electronic power steering system, an electronic power steering system, a control device for an electronic power steering system, and a vehicle. Background Art

[0004] The adoption rate of electronic power steering systems in passenger cars and commercial vehicles is increasing year by year. These systems provide steering assistance to drivers, making vehicle control easier. However, compared to traditional mechanical and hydraulic steering systems, electronic power steering systems carry an increased risk of electronic control system failure, with loss of the ignition signal (KL15 signal) being a typical failure mode.

[0005] In related technologies, the controller of the electronic power steering system is awakened by an ignition signal. When the ignition signal is abnormal, the controller enters a dormant state, and the electronic power steering system is unable to provide steering assistance, causing the steering assistance to become abnormal, resulting in a safety hazard for the vehicle. Summary of the Invention

[0006] The present invention aims to at least partially address one of the technical problems in the related art. To this end, a first object of the present invention is to provide a control method for an electronic power steering system. This method can control the electronic power steering system to provide steering assistance to the vehicle based on a steering wheel torque signal and a vehicle speed signal when an abnormal vehicle ignition signal occurs, thereby avoiding safety hazards caused by abnormal steering assistance and improving vehicle safety.

[0007] A second object of the present invention is to provide an electronic power steering system.

[0008] A third object of the present invention is to provide a control device for an electronic power steering system.

[0009] A fourth object of the present invention is to provide a vehicle.

[0010] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention proposes a control method for an electronic power steering system, the method comprising: when the vehicle ignition signal is abnormal, obtaining a steering wheel torque signal and a vehicle speed signal; when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, controlling the electronic power steering system to provide steering assistance based on a first preset vehicle speed; when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold, controlling the electronic power steering system to stop providing steering assistance.

[0011] According to an embodiment of the present invention, a control method for an electronic power steering system first obtains a steering wheel torque signal and a vehicle speed signal when a vehicle ignition signal is abnormal. When the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, a controller controls the electronic power steering system to provide steering assistance based on the first preset vehicle speed. When the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold, the controller controls the electronic power steering system to stop providing steering assistance. Thus, when the vehicle ignition signal is abnormal, the method can control the electronic power steering system to provide steering assistance based on the steering wheel torque signal and the vehicle speed signal, thereby avoiding safety hazards caused by abnormal steering assistance and improving vehicle safety.

[0012] In addition, the control method of the electronic power steering system according to the above embodiment of the present invention may also have the following additional technical features:

[0013] According to an embodiment of the present invention, the method further includes: when the vehicle speed signal is normal, controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal.

[0014] According to one embodiment of the present invention, the whole vehicle speed signal includes a first speed signal obtained based on a speed sensor, the whole vehicle speed signal being abnormal means the first speed signal is abnormal, and the whole vehicle speed signal being normal means the first speed signal is normal; the whole vehicle speed signal includes a second speed signal obtained based on a wheel speed signal, the whole vehicle speed signal being abnormal means the second speed signal is abnormal, and the whole vehicle speed signal being normal means the second speed signal is normal; the whole vehicle speed signal includes a first speed signal obtained based on a speed sensor and a second speed signal obtained based on a wheel speed signal, the whole vehicle speed signal being abnormal means both the first speed signal and the second speed signal are abnormal, and the whole vehicle speed signal being normal means at least one of the first speed signal and the second speed signal is normal.

[0015] According to one embodiment of the present invention, when the vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal, controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal includes: when the first vehicle speed signal is normal, controlling the electronic power steering system to provide steering assistance based on the first vehicle speed signal; when the first vehicle speed signal is abnormal and the second vehicle speed signal is normal, controlling the electronic power steering system to provide steering assistance based on the second vehicle speed signal.

[0016] According to one embodiment of the present invention, controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal includes: controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal when the vehicle speed signal is not zero; and controlling the electronic power steering system to provide steering assistance based on a second preset vehicle speed when the vehicle speed signal is zero.

[0017] According to one embodiment of the present invention, the method further includes: obtaining the effective value of the first vehicle speed signal, and determining that the first vehicle speed signal is normal when the effective value of the first vehicle speed signal is normal; determining that the first vehicle speed signal is abnormal when the effective value of the first vehicle speed signal is abnormal; obtaining the effective value of the wheel speed signal, and determining that the second vehicle speed signal is normal when the effective value of the wheel speed signal is normal; and determining that the second vehicle speed signal is abnormal when the effective value of the wheel speed signal is abnormal.

[0018] According to one embodiment of the present invention, the vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal. The method further includes: when the vehicle ignition signal is normal and the first vehicle speed signal is normal, controlling the electronic power steering system to provide steering assistance based on the first vehicle speed signal; when the vehicle ignition signal is normal and the first vehicle speed signal is abnormal, controlling the electronic power steering system to provide steering assistance based on the second vehicle speed signal.

[0019] To achieve the above-mentioned purpose, the second embodiment of the present invention proposes an electronic power steering system, including: a memory and a processor, wherein the memory stores a program that can be run on the processor, and when the processor executes the program, the control method of the above-mentioned electronic power steering system is implemented.

[0020] According to the electronic power steering system of an embodiment of the present invention, through the above-mentioned control method of the electronic power steering system, when the vehicle ignition signal is abnormal, the vehicle can be assisted in steering according to the steering wheel torque signal and the vehicle speed signal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the entire vehicle.

[0021] To achieve the above-mentioned objectives, an embodiment of the third aspect of the present invention proposes a control device for an electronic power steering system, the device comprising: an acquisition module for acquiring a steering wheel torque signal and a vehicle speed signal when the vehicle ignition signal is abnormal; a control module for controlling the electronic power steering system to provide steering assistance based on a first preset vehicle speed when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, and controlling the electronic power steering system to stop providing steering assistance when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold.

[0022] According to the control device for an electronic power steering system of an embodiment of the present invention, the acquisition module acquires the steering wheel torque signal and the vehicle speed signal when the vehicle ignition signal is abnormal. The control module controls the electronic power steering system to provide steering assistance based on a first preset vehicle speed when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold. Furthermore, when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold, the control module controls the electronic power steering system to stop providing steering assistance. Thus, the device can control the electronic power steering system to provide steering assistance to the vehicle based on the steering wheel torque signal and the vehicle speed signal when the vehicle ignition signal is abnormal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the vehicle.

[0023] To achieve the above-mentioned objectives, a fourth embodiment of the present invention provides a vehicle comprising the above-mentioned electronic power steering system, or a control device for the above-mentioned electronic power steering system.

[0024] According to an embodiment of the present invention, a vehicle including the above-mentioned electronic power steering system or a control device for an electronic power steering system can control the electronic power steering system to provide steering assistance to the vehicle based on a steering wheel torque signal and a vehicle speed signal when the ignition signal of the entire vehicle is abnormal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the entire vehicle.

[0025] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a flow chart of a control method of an electronic power steering system according to an embodiment of the present invention;

[0027] FIG2 is a block diagram of an electronic power steering system according to an embodiment of the present invention;

[0028] 3 is a block diagram of a control device for an electronic power steering system according to an embodiment of the present invention;

[0029] FIG4 is a block diagram of a vehicle according to an embodiment of the present invention;

[0030] FIG5 is a block diagram of a vehicle according to another embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0032] The following describes an electronic power steering system control method, an electronic power steering system, a control device for an electronic power steering system, and a vehicle according to embodiments of the present invention with reference to the accompanying drawings.

[0033] FIG1 is a flow chart of a control method of an electronic power steering system according to an embodiment of the present invention.

[0034] As shown in FIG1 , the control method of the electronic power steering system according to the embodiment of the present invention may include the following steps:

[0035] S1, when the vehicle ignition signal is abnormal, obtain the steering wheel torque signal and the vehicle speed signal.

[0036] S2: When the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, the electronic power steering system is controlled to provide steering assistance based on a first preset vehicle speed. The preset threshold and the first preset vehicle speed may be calibrated according to actual conditions.

[0037] S3: When the vehicle speed signal is abnormal and the change rate of the steering wheel torque signal is less than or equal to a preset threshold, the electronic power steering system is controlled to stop providing steering assistance.

[0038] Specifically, when the vehicle is powered on, the ignition signal (i.e., the KL15 signal) is transmitted via a hardwire to the controller of the electronic power steering system to enable the electronic power steering system to operate. The electronic power steering system receives the vehicle speed signal via the CAN (Controller Area Network) network and provides steering assistance to the vehicle based on the vehicle speed: when the vehicle is turning at low speed, the electronic power steering system provides sufficient power torque to assist the driver in completing the steering operation, making steering easier and reducing the driver's burden; when the vehicle is turning at high speed, the EPS system provides a smaller power torque to ensure that the driver has a good sense of the road and ensure the stability of the vehicle. It should be noted that the correspondence between vehicle speed and power torque, i.e., the power curve, can be obtained during the vehicle calibration process and stored in the controller of the electronic power steering system.

[0039] When the vehicle ignition signal is abnormal, such as poor contact of the hard wire transmitting the KL15 signal or the ignition signal is lost during the transmission process, the controller of the electronic power steering system does not enter the sleep state, but continues to receive the vehicle speed signal through the CAN network, and obtains the steering wheel torque signal through the torque signal sensor arranged at the steering wheel. When the vehicle speed signal is abnormal, such as poor contact of the CAN network signal line, the controller compares the change rate of the steering wheel torque signal with the preset threshold. If the change rate of the steering wheel torque signal is greater than the preset threshold within a certain period of time, it means that the driver is performing a steering operation, and the controller can control the electronic power steering system to provide steering assistance to the vehicle according to the power torque corresponding to the first preset speed (such as 80Km / h); if the change rate of the steering wheel torque signal is less than or equal to the preset threshold within a certain period of time, it means that the driver is not driving the vehicle at this time, and the controller controls the electronic power steering system to stop providing steering assistance.

[0040] Therefore, the control method of the electronic power steering system in the embodiment of the present invention can control the electronic power steering system to provide steering assistance to the vehicle according to the steering wheel torque signal and the vehicle speed signal when the vehicle ignition signal is abnormal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the vehicle.

[0041] According to an embodiment of the present invention, the method further includes: when the vehicle speed signal is normal, controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal.

[0042] That is to say, when the vehicle speed signal is normal, the controller can control the electronic power steering system to provide power torque according to the vehicle speed corresponding to the vehicle speed signal to assist in steering the vehicle.

[0043] According to one embodiment of the present invention, the vehicle speed signal includes a first speed signal obtained based on a speed sensor, an abnormal vehicle speed signal means the first speed signal is abnormal, and a normal vehicle speed signal means the first speed signal is normal; the vehicle speed signal includes a second speed signal obtained based on a wheel speed signal, an abnormal vehicle speed signal means the second speed signal is abnormal, and a normal vehicle speed signal means the second speed signal is normal; the vehicle speed signal includes a first speed signal obtained based on the speed sensor and a second speed signal obtained based on the wheel speed signal, an abnormal vehicle speed signal means both the first speed signal and the second speed signal are abnormal, and a normal vehicle speed signal means at least one of the first speed signal and the second speed signal is normal.

[0044] Specifically, the vehicle speed sensor can obtain the vehicle motor speed and convert it into a first vehicle speed signal. This signal is then transmitted to the electronic power steering system controller via the CAN network, and the first vehicle speed signal is used as the vehicle speed signal. If the vehicle speed signal is abnormal, the first vehicle speed signal is abnormal; if the vehicle speed signal is normal, the first vehicle speed signal is normal.

[0045] The electronic hydraulic braking system acquires wheel speed signals from the left and right front wheels, transmitting them via the CAN network to the electronic power steering system's controller. The controller then calculates the speeds of the left and right front wheels to generate a second vehicle speed signal, which it uses as the overall vehicle speed signal. An abnormal overall vehicle speed signal indicates an abnormality in the second vehicle speed signal; a normal overall vehicle speed signal indicates a normal second vehicle speed signal.

[0046] Furthermore, the controller can also use the first and second vehicle speed signals as a combined vehicle speed signal. When the vehicle speed signal is abnormal, both the first and second vehicle speed signals are abnormal; and when the vehicle speed signal is normal, at least one of the first and second vehicle speed signals is normal.

[0047] According to one embodiment of the present invention, when the vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal, the electronic power steering system is controlled to provide steering assistance based on the vehicle speed signal, including: when the first vehicle speed signal is normal, the electronic power steering system is controlled to provide steering assistance based on the first vehicle speed signal; when the first vehicle speed signal is abnormal and the second vehicle speed signal is normal, the electronic power steering system is controlled to provide steering assistance based on the second vehicle speed signal.

[0048] Specifically, the vehicle speed sensor can obtain the speed of the vehicle's motor, convert it into a first vehicle speed signal, and transmit it to the controller of the electronic power steering system via the CAN network. The electronic hydraulic braking system can respectively obtain the wheel speed signals corresponding to the left and right front wheels, and transmit the wheel speed signals to the controller of the electronic power steering system via the CAN network. The controller calculates based on the left and right front wheel speeds to obtain a second vehicle speed signal. When the vehicle ignition signal is abnormal and the first vehicle speed signal is normal, the controller can control the electronic power steering system to provide a power torque to assist the vehicle in steering according to the vehicle speed corresponding to the first vehicle speed signal. When the first vehicle speed signal is abnormal and the second vehicle speed signal is normal, the controller can control the electronic power steering system to provide a power torque to assist the vehicle in steering according to the vehicle speed corresponding to the second vehicle speed signal.

[0049] When the first vehicle speed signal is abnormal and the second vehicle speed signal is abnormal, the controller compares the change rate of the steering wheel torque signal with a preset threshold value. If the change rate of the steering wheel torque signal is greater than the preset threshold value within a certain period of time, it means that the driver is performing a steering operation, and the controller can control the electronic power steering system to provide steering assistance to the vehicle according to the power torque corresponding to the first preset vehicle speed (such as 80Km / h); if the change rate of the steering wheel torque signal is less than or equal to the preset threshold value within a certain period of time, it means that the driver is not driving the vehicle at this time, and the controller controls the electronic power steering system to stop providing steering assistance.

[0050] According to one embodiment of the present invention, controlling an electronic power steering system to provide steering assistance based on a vehicle speed signal includes: controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal when the vehicle speed signal is non-zero; and controlling the electronic power steering system to provide steering assistance based on a second preset vehicle speed when the vehicle speed signal is zero. The second preset vehicle speed may be calibrated based on actual conditions.

[0051] Specifically, when the vehicle ignition signal is abnormal, the vehicle speed signal is normal and the vehicle speed signal is not zero, the controller can control the electronic power steering system to provide power torque according to the vehicle speed corresponding to the vehicle speed signal to assist in steering the vehicle; when the first vehicle speed signal is zero, if within a certain period of time, the change rate of the steering wheel torque signal is greater than the preset threshold, it means that the driver is performing a steering operation, and the controller can control the electronic power steering system to provide steering assistance to the vehicle according to the power torque corresponding to the second preset speed.

[0052] According to one embodiment of the present invention, the above method also includes: obtaining the effective value of the first vehicle speed signal, and determining that the first vehicle speed signal is normal when the effective value of the first vehicle speed signal is normal; determining that the first vehicle speed signal is abnormal when the effective value of the first vehicle speed signal is abnormal; obtaining the effective value of the wheel speed signal, and determining that the second vehicle speed signal is normal when the effective value of the wheel speed signal is normal; and determining that the second vehicle speed signal is abnormal when the effective value of the wheel speed signal is abnormal.

[0053] Specifically, the vehicle speed sensor can obtain the vehicle motor speed, convert it into a first vehicle speed signal, and simultaneously determine whether the first vehicle speed signal is valid, obtaining a first vehicle speed signal effective value. The vehicle speed sensor then transmits the first vehicle speed signal and the first vehicle speed signal effective value to the electronic power steering system controller via the CAN network. If the first vehicle speed signal effective value is normal, the controller determines that the first vehicle speed signal is normal. If the first vehicle speed signal effective value is abnormal, such as due to poor contact in the CAN network cable or loss of the first vehicle speed signal effective value during transmission, the controller determines that the first vehicle speed signal is abnormal.

[0054] The electronic hydraulic braking system can obtain the left front wheel speed signal and the right front wheel speed signal respectively, and determine whether the left front wheel speed signal and the right front wheel speed signal are valid, respectively, to obtain the effective value of the left front wheel speed signal and the effective value of the right front wheel speed signal. The electronic hydraulic braking system transmits the left front wheel speed signal, the right front wheel speed signal, the effective value of the left front wheel speed signal, and the effective value of the right front wheel speed signal via the CAN network to the controller of the electronic power steering system. The controller calculates based on the left front wheel speed signal and the right front wheel speed signal to obtain a second vehicle speed signal. When the effective value of the left front wheel speed signal and the effective value of the right front wheel speed signal are normal, the controller determines that the second vehicle speed signal is normal; when the effective value of the left front wheel speed signal and the effective value of the right front wheel speed signal are abnormal, the controller determines that the second vehicle speed signal is abnormal.

[0055] According to one embodiment of the present invention, the vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal. The above method also includes: when the vehicle ignition signal is normal and the first vehicle speed signal is normal, controlling the electronic power steering system to provide steering assistance based on the first vehicle speed signal; when the vehicle ignition signal is normal and the first vehicle speed signal is abnormal, controlling the electronic power steering system to provide steering assistance based on the second vehicle speed signal.

[0056] Specifically, the vehicle speed sensor can obtain the speed of the vehicle's motor, convert it into a first vehicle speed signal, and transmit it to the controller of the electronic power steering system via the CAN network. The electronic hydraulic brake system can obtain the wheel speed signals corresponding to the left and right front wheels respectively, and transmit the wheel speed signals to the controller of the electronic power steering system via the CAN network. The controller calculates based on the left and right front wheel speeds to obtain a second vehicle speed signal. When the vehicle ignition signal and the first vehicle speed signal are normal, the controller can control the electronic power steering system to provide power torque to assist steering the vehicle based on the vehicle speed corresponding to the first vehicle speed signal. When the vehicle ignition signal is normal and the first vehicle speed signal is abnormal, the controller can control the electronic power steering system to provide power torque to assist steering the vehicle based on the vehicle speed corresponding to the second vehicle speed signal.

[0057] In summary, according to the control method of the electronic power steering system of an embodiment of the present invention, when the vehicle ignition signal is abnormal, the steering wheel torque signal and the vehicle speed signal are first obtained. When the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, the controller controls the electronic power steering system to provide steering assistance based on the first preset vehicle speed. When the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold, the controller controls the electronic power steering system to stop providing steering assistance. As a result, this method can control the electronic power steering system to provide steering assistance to the vehicle based on the steering wheel torque signal and the vehicle speed signal when the vehicle ignition signal is abnormal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the vehicle.

[0058] Corresponding to the above embodiment, the present invention further proposes an electronic power steering system.

[0059] FIG2 is a block diagram of an electronic power steering system according to an embodiment of the present invention.

[0060] As shown in FIG2 , an electronic power steering system 200 according to an embodiment of the present invention includes a memory 210 and a processor 220 . The memory 210 stores a program that can be run on the processor 220 . When the processor 220 executes the program, the control method of the electronic power steering system described above is implemented.

[0061] According to the electronic power steering system of an embodiment of the present invention, through the above-mentioned control method of the electronic power steering system, when the vehicle ignition signal is abnormal, the vehicle can be assisted in steering according to the steering wheel torque signal and the vehicle speed signal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the entire vehicle.

[0062] Corresponding to the above embodiment, the present invention further proposes a control device for an electronic power steering system.

[0063] FIG3 is a block diagram of a control device for an electronic power steering system according to an embodiment of the present invention.

[0064] As shown in FIG3 , the control device 100 of the electronic power steering system according to the embodiment of the present invention may include: an acquisition module 110 and a control module 120 .

[0065] The acquisition module 110 is configured to acquire a steering wheel torque signal and a vehicle speed signal when the vehicle ignition signal is abnormal. The control module 120 is configured to control the electronic power steering system to provide steering assistance based on a first preset vehicle speed when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, and to control the electronic power steering system to stop providing steering assistance when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold.

[0066] According to one embodiment of the present invention, the control module 120 is further configured to control the electronic power steering system to provide steering assistance based on the vehicle speed signal when the vehicle speed signal is normal.

[0067] According to one embodiment of the present invention, the vehicle speed signal includes a first speed signal obtained based on a speed sensor, an abnormal vehicle speed signal means the first speed signal is abnormal, and a normal vehicle speed signal means the first speed signal is normal; the vehicle speed signal includes a second speed signal obtained based on a wheel speed signal, an abnormal vehicle speed signal means the second speed signal is abnormal, and a normal vehicle speed signal means the second speed signal is normal; the vehicle speed signal includes a first speed signal obtained based on the speed sensor and a second speed signal obtained based on the wheel speed signal, an abnormal vehicle speed signal means both the first speed signal and the second speed signal are abnormal, and a normal vehicle speed signal means at least one of the first speed signal and the second speed signal is normal.

[0068] According to one embodiment of the present invention, when the vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal, the control module 120 controls the electronic power steering system to provide steering assistance based on the vehicle speed signal. Specifically, when the first vehicle speed signal is normal, the electronic power steering system is controlled to provide steering assistance based on the first vehicle speed signal; when the first vehicle speed signal is abnormal and the second vehicle speed signal is normal, the electronic power steering system is controlled to provide steering assistance based on the second vehicle speed signal.

[0069] According to one embodiment of the present invention, the control module 120 controls the electronic power steering system to provide steering assistance based on the vehicle speed signal. Specifically, when the vehicle speed signal is not zero, the electronic power steering system is controlled to provide steering assistance based on the vehicle speed signal; when the vehicle speed signal is zero, the electronic power steering system is controlled to provide steering assistance based on a second preset speed.

[0070] According to one embodiment of the present invention, the control module 120 is further used to obtain the effective value of the first vehicle speed signal, and determine that the first vehicle speed signal is normal when the effective value of the first vehicle speed signal is normal; and determine that the first vehicle speed signal is abnormal when the effective value of the first vehicle speed signal is abnormal; and obtain the effective value of the wheel speed signal, and determine that the second vehicle speed signal is normal when the effective value of the wheel speed signal is normal; and determine that the second vehicle speed signal is abnormal when the effective value of the wheel speed signal is abnormal.

[0071] According to one embodiment of the present invention, the vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal. The control module 120 is also used to control the electronic power steering system to provide steering assistance based on the first vehicle speed signal when the vehicle ignition signal and the first vehicle speed signal are normal; and to control the electronic power steering system to provide steering assistance based on the second vehicle speed signal when the vehicle ignition signal is normal and the first vehicle speed signal is abnormal.

[0072] It should be noted that for details not disclosed in the control device of the electronic power steering system in the embodiment of the present invention, please refer to the details disclosed in the control method of the electronic power steering system in the embodiment of the present invention, and the details will not be repeated here.

[0073] According to the control device for an electronic power steering system of an embodiment of the present invention, the acquisition module acquires the steering wheel torque signal and the vehicle speed signal when the vehicle ignition signal is abnormal. The control module controls the electronic power steering system to provide steering assistance based on a first preset vehicle speed when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold. Furthermore, when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold, the control module controls the electronic power steering system to stop providing steering assistance. Thus, the device can control the electronic power steering system to provide steering assistance to the vehicle based on the steering wheel torque signal and the vehicle speed signal when the vehicle ignition signal is abnormal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the vehicle.

[0074] Corresponding to the above embodiment, the present invention also provides a vehicle.

[0075] As shown in FIG4 , a vehicle 300 according to an embodiment of the present invention includes the aforementioned electronic power steering system 200 , or, as shown in FIG5 , further includes the aforementioned control device 100 for the electronic power steering system.

[0076] According to an embodiment of the present invention, a vehicle including the above-mentioned electronic power steering system or a control device for an electronic power steering system can control the electronic power steering system to provide steering assistance to the vehicle based on a steering wheel torque signal and a vehicle speed signal when the ignition signal of the entire vehicle is abnormal, thereby avoiding safety hazards caused by abnormal steering assistance and improving the safety of the entire vehicle.

[0077] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection having one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0078] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0079] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0081] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0082] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A control method for an electronic power steering system, characterized in that: The method comprises: When the vehicle ignition signal is abnormal, obtain the steering wheel torque signal and vehicle speed signal; When the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, controlling the electronic power steering system to provide steering assistance based on a first preset vehicle speed; When the vehicle speed signal is abnormal and the change rate of the steering wheel torque signal is less than or equal to the preset threshold, the electronic power steering system is controlled to stop providing steering assistance.

2. The method according to claim 1, characterized in that The method further comprises: When the vehicle speed signal is normal, the electronic power steering system is controlled to provide steering assistance based on the vehicle speed signal.

3. The method according to claim 2, characterized in that The vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor, the abnormal vehicle speed signal means the first vehicle speed signal is abnormal, and the normal vehicle speed signal means the first vehicle speed signal is normal; The vehicle speed signal includes a second vehicle speed signal obtained based on the wheel speed signal, the abnormal vehicle speed signal means the second vehicle speed signal is abnormal, and the normal vehicle speed signal means the second vehicle speed signal is normal; The vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal. The abnormal vehicle speed signal means that both the first vehicle speed signal and the second vehicle speed signal are abnormal. The normal vehicle speed signal means that at least one of the first vehicle speed signal and the second vehicle speed signal is normal.

4. The method according to claim 3, characterized in that When the vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal, controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal includes: When the first vehicle speed signal is normal, controlling the electronic power steering system to provide steering assistance based on the first vehicle speed signal; When the first vehicle speed signal is abnormal and the second vehicle speed signal is normal, the electronic power steering system is controlled to provide steering assistance based on the second vehicle speed signal.

5. The method according to any one of claims 2 to 4, characterized in that: The controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal includes: When the vehicle speed signal is not zero, controlling the electronic power steering system to provide steering assistance based on the vehicle speed signal; When the vehicle speed signal is zero, the electronic power steering system is controlled to provide steering assistance based on a second preset vehicle speed.

6. The method according to claim 3, characterized in that The method further comprises: Acquiring a valid value of a first vehicle speed signal, and determining that the first vehicle speed signal is normal if the valid value of the first vehicle speed signal is normal; and determining that the first vehicle speed signal is abnormal if the valid value of the first vehicle speed signal is abnormal; Obtaining a wheel speed signal effective value, and determining that the second vehicle speed signal is normal when the wheel speed signal effective value is normal; and determining that the second vehicle speed signal is abnormal when the wheel speed signal effective value is abnormal.

7. The method according to claim 1, characterized in that The vehicle speed signal includes a first vehicle speed signal obtained based on a vehicle speed sensor and a second vehicle speed signal obtained based on a wheel speed signal. The method further includes: When the vehicle ignition signal and the first vehicle speed signal are normal, controlling the electronic power steering system to provide steering assistance based on the first vehicle speed signal; When the vehicle ignition signal is normal and the first vehicle speed signal is abnormal, the electronic power steering system is controlled to provide steering assistance based on the second vehicle speed signal.

8. An electronic power steering system, characterized in that: include: A memory and a processor, wherein the memory stores a program that can be run on the processor, and when the processor executes the program, the control method of the electronic power steering system according to any one of claims 1 to 7 is implemented.

9. A control device for an electronic power steering system, characterized in that: The device comprises: The acquisition module is used to obtain the steering wheel torque signal and vehicle speed signal when the vehicle ignition signal is abnormal; The control module is configured to control the electronic power steering system to provide steering assistance based on a first preset vehicle speed when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is greater than a preset threshold, and to control the electronic power steering system to stop providing steering assistance when the vehicle speed signal is abnormal and the rate of change of the steering wheel torque signal is less than or equal to the preset threshold.

10. A vehicle, characterized in that: The method comprises the electronic power steering system according to claim 8 or the control device of the electronic power steering system according to claim 9.

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